Leases - NPC - Schedule of Operating and Finance Lease (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Right-of-use assets:
Operating leases	$ 545	$ 524
Finance leases	418	448
Total right-of-use assets	$ 963	$ 972
Operating lease right-of-use asset, statement of financial position	Other assets	Other assets
Finance lease right-of-use asset, statement of financial position	Other assets	Other assets
Lease liabilities:
Operating leases	$ 605	$ 577
Finance leases	432	463
Total lease liabilities	$ 1,037	$ 1,040
Operating lease liability, statement of financial position	Other current liabilities, Other long-term liabilities	Other current liabilities, Other long-term liabilities
Finance lease liability, statement of financial position	Other current liabilities, Other long-term liabilities	Other current liabilities, Other long-term liabilities
NPC
Right-of-use assets:
Operating leases	$ 9	$ 10
Finance leases	303	326
Total right-of-use assets	$ 312	$ 336
Operating lease right-of-use asset, statement of financial position	Other assets	Other assets
Finance lease right-of-use asset, statement of financial position	Other assets	Other assets
Lease liabilities:
Operating leases	$ 11	$ 13
Finance leases	313	336
Total lease liabilities	$ 324	$ 349
Operating lease liability, statement of financial position	Other current liabilities, Other long-term liabilities	Other current liabilities, Other long-term liabilities
Finance lease liability, statement of financial position	Other current liabilities, Other long-term liabilities	Other current liabilities, Other long-term liabilities